Specifications:Navigator2 is designed so that the momentary push button on the front right causes the robot to cut the left motor off so the only motor running is the right motor this causes Navigator2 to turn left because the only motor runninhg is the right motor this is the same collison system I used on navigator1 also I used a resistor to slow the fast dc motors down.Navigator2,s power supply is two AA nimh Nickel-Metal Hydride batterys their 1.2v batterys I used these so my 3v 40mA solar cell could safely charge Navigator2,s batterys and and I used a led to keep the batteys juice from leaking out when the solar cell charges the batterys also Navigator2 has a on indicating led yellow. Problems:I had a few problems like Navigator2 is an indoor robot and its solar cell does work under indoor light but it does work around a window are a door with glass in it.Another problem is that Navigator2 is some what back heavy so im going to try to find some method to fix this problem. Parts: Pc board which I used for Navigator2,s body it came from radio shack cost $2.69. Two dc motors 1.5-3vdc these came from radio shack cost $1.49 each Solar cell its size is 2.40 inchs I got this from www.allelectronics.com for $3.50 plus shipping and handling $6. Two AA battery holder it came from radio shack it cost $1.49 Total:$16.66 I had all the other parts already. Dimensions: Length: 3.8 inchs Width: 5.5 inchs Height: 2.2 inchs Weight: N/A Time to build:Im not sure I worked on Navigator2 on and off. Please check my web site out at: http://hometown.aol.com/botnerd/StevensRoboticsindex.html Email: Botnerd@aol.com